package  com.yishun.springboot.util;

import java.nio.charset.Charset;
import java.security.MessageDigest;
import java.security.NoSuchAlgorithmException;

/**
 * @author HuangShilin
 * @date 2019-04-22 18:07
 */
public class SignatureUtil {
    /**
     * 获取签名
     *
     * @param: [apiKey, apiVersion, engCode, projectCode, timestamp, body]
     * @return: java.lang.String
     * @author HuangShilin
     * @date 2019-04-24 17:54
     */
    public static String getSignature(String apiKey, String apiVersion,
                                      String engCode, String projectCode,
                                      String timestamp, String body) {
        String str4MD5 = String.format("api_key%sapi_version%sbody%seng_code=%sproject_code=%stimestamp%s",
                apiKey, apiVersion, body.isEmpty() ? "{}" : body, engCode, projectCode, timestamp);
        return getMD5Code(str4MD5);
    }

    public static String getMD5Code(String strObj) {
        String resultString = null;
        try {
            resultString = new String(strObj);
            MessageDigest md = MessageDigest.getInstance("MD5");
            Charset charset = Charset.forName("UTF-8");
            resultString = byteToString(md.digest(strObj.getBytes(charset)));
        } catch (NoSuchAlgorithmException ex) {
            ex.printStackTrace();
        }
        return resultString;
    }

    // 转换字节数组为16进制字串
    private static String byteToString(byte[] bByte) {
        StringBuffer sBuffer = new StringBuffer();
        for (int i = 0; i < bByte.length; i++) {
            sBuffer.append(byteToArrayString(bByte[i]));
        }
        return sBuffer.toString();
    }

    private static String byteToArrayString(byte bByte) {
        int iRet = bByte;
        if (iRet < 0) {
            iRet += 256;
        }
        int iD1 = iRet / 16;
        int iD2 = iRet % 16;
        return strDigits[iD1] + strDigits[iD2];
    }

    // 全局数组
    private final static String[] strDigits = {"0", "1", "2", "3", "4", "5", "6", "7", "8", "9",
            "A", "B", "C", "D", "E", "F"};
}
